Elecraft DSP vs Audio Filter?

[Fred (FL)]

Isn't the Elecraft DSP option, really an
audio-frequency device?  I don't believe it in the IF
string at all, but
I might be wrong.  So I wonder how folks are comparing
a audio DSP vs an audio filter .... sounds a little
like
comparing apples to apples.

I believe Icom's new IC-7000, has an IF DSP capability
- quite remarkable owners relate.

Can someone clarify the benefits and HOW's, of the K2
DSP option.  What does it offer, over and above the
standard K2 filters and option SSB filters?

Still have not wired my TenTec mike, for my new
K2.  Bummer ......

Thanks, 73's
Fred N3CSY
6/01

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[KK7P]

> Can someone clarify the benefits and HOW's, of the K2
> DSP option.  What does it offer, over and above the
> standard K2 filters and option SSB filters?

Please read <http://www.elecraft.com/KDSP2/kdsp2design.pdf> for
background on the design choices made for the KDSP2.  It also highlights
some of the features that set it apart from other DSPs, and how it
augments the IF filters in the K2.

You can also download the manuals for the KDSP2 and the KAF2 from the
Elecraft website and compare the specs (found on the first couple of
pages) of the two products.

73,

Lyle KK7P

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[Steven Pituch]

Hi Fred,
The K2 has one of the best IF sections around.  Because it is so good, it
does not need IF filtering. So they decided to make an AF DSP filter that
was a lot more affordable and had a real benefit to the K2.  Being single
conversion the K2's IF filter is close to the front end.  It narrows down
the signal before a lot of internally generated crap appears.  Triple and
quadruple conversion receivers need IF DSP because so much garabage is
introduced into the signal after the front end and before the IF filtering.
When you hear that an expensive radio has just been "improved" and had
roofing filters installed near its front end to clean up the garbage, I
think they should go back to the drawing board and dream up a cleaner radio.
But then the K2 is available so why would anyone want to consider anything
else?  
How is that for a "nontechnical " answer? ;o)   ( flame suit on)

The K2 IF variable width filter is very good.  It makes the K2 one of the
best radios for fighting adjacent interference.  When that 2000 W CW signal
camps out 300 Hz away from your QRP friend, its this filter that makes the
K2 the easiest radio to use to hear your contact.  It is ahead of the AGC so
you generally narrow down the IF filter until you can receive the other guy
and minimize the interference from the other station.  That way the
interfering station does not pump the AGC.

The audio DSP filters are much sharper.  Once you have maximized the IF
filter, you can get additional isolation by kicking in the audio DSP
filters.  It took me awhile to figure out the DSP but it is very nice and
apparently one of the best around.

I have even optimized the IF and DSP on my K2 for RTTY and as an example
have some waterfall displays of the filters at:
http://users.ev1.net/~spituch/Steve's%20Page/Radio/RTTY/RTTY.html
>From the photos you can see how well the DSP works.  Also you can center the
DSP filters very easily by just watching the waterfall display.

Regards,
Steve, W2MY

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[Andrew Moore-4]

I find the KX1's "CW feedback" announcements incredibly useful while
operating mobile.  Eric/Wayne - have you considered incorporating this
wonderful feature into a future firmware version for the K1?

I'm particularly impressed with how well it's implemented: it announces the
frequency only when the Band button is pressed; it doesn't feel the need to
announce the digits after the decimal point.  It says just enough - not too
little, not too much.



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[peter gerba]

I agree with Steve for the most part. It's going to be very hard to beat the
K2's design. I have a KAF2 and use it to take the high end hiss out of some
headphones. I don't think it's necessary for normal CW operation. I've had
some DSP in other radios. I don't like the way it sounds. Most CW OPs do a
great amount of filtering between their ears. I can't speak to K2 W/DSP and
SSB. If you're set on DSP, the unit's placement in the K2 IF is a better bet
than on some more expensive triple and quad conversion rigs. Placing DSP in
the best IF in one of those radios (if done properly) is very expensive. See
Racal and WJ receivers.. and I guess the new Icom 7800 and the hi end Yaseu
radios. Think about what those rigs cost and look what Wayne did with a
simple design.

pete, kn6bi



Hi Fred,
The K2 has one of the best IF sections around.  Because it is so good, it
does not need IF filtering. So they decided to make an AF DSP filter that

CLIP

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[wayne burdick]

Andrew Moore wrote:

> I find the KX1's "CW feedback" announcements incredibly useful while
> operating mobile.

Glad you like it.


> Eric/Wayne - have you considered incorporating this
> wonderful feature into a future firmware version for the K1?

Last time I checked there were about 10 bytes of code space left in the
K1, so probably not :)  While we could upgrade to a larger micro
someday, this isn't on the present schedule.

Of course the KX1 is easier to use in a mobile situation anyway,
assuming you're setting the KX1 on the passenger seat or putting it on
the column, etc. The top-mounted controls are ideal for such
circumstances.


>
> I'm particularly impressed with how well it's implemented: it
> announces the
> frequency only when the Band button is pressed; it doesn't feel the
> need to
> announce the digits after the decimal point.  It says just enough -
> not too
> little, not too much.

Thanks. We tested and refined the KX1's Morse feedback by turning the
radio around backwards so we couldn't see the display.

Our blind customers love the KX1 because of the 100% Morse feedback
(even menu text). But it's also useful when you're half asleep, eyes
closed, in the wee hours of a backpacking Field Day. Or when operating
surreptitiously late at night in bed, with the lights out  :)

73,
Wayne
N6KR

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[peter gerba]

Correction:
unit's placement in the K2 IF is a better bet.. should be "Audio Path".

p.

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of peter gerba
Sent: Thursday, June 01, 2006 8:44 PM
To: Steven Pituch; [hidden email]
Subject: RE: [Elecraft] Elecraft DSP vs Audio Filter?


I agree with Steve for the most part. It's going to be very hard to beat the
K2's design. I have a KAF2 and use it to take the high end hiss out of some
headphones. I don't think it's necessary for normal CW operation. I've had
some DSP in other radios. I don't like the way it sounds. Most CW OPs do a
great amount of filtering between their ears. I can't speak to K2 W/DSP and
SSB. If you're set on DSP, the unit's placement in the K2 IF is a better bet
than on some more expensive triple and quad conversion rigs. Placing DSP in
the best IF in one of those radios (if done properly) is very expensive. See
Racal and WJ receivers.. and I guess the new Icom 7800 and the hi end Yaseu
radios. Think about what those rigs cost and look what Wayne did with a
simple design.

pete, kn6bi



Hi Fred,
The K2 has one of the best IF sections around.  Because it is so good, it
does not need IF filtering. So they decided to make an AF DSP filter that

CLIP

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[Dave, G4AON]

Fred

Another consideration is the current drawn by the DSP unit, if you intend to operate your K2 from the internal battery option a fully loaded K2 (including DSP) can approach 350 mA.

73's Dave G4AON
K2 #1892
---------------------------------------------------
Can someone clarify the benefits and HOW's, of the K2
DSP option.  What does it offer, over and above the
standard K2 filters and option SSB filters?

Still have not wired my TenTec mike, for my new
K2.  Bummer ......

Thanks, 73's
Fred N3CSY

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[KK7P]

  > Another consideration is the current drawn by the DSP unit, if you
> intend to operate your K2 from the internal battery option a fully
> loaded K2 (including DSP) can approach 350 mA.

If the current band conditions don't require the use of the DSP, it can
be placed in bypass mode where its current consumption drops to about 10 mA.

73,

Lyle KK7P

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[Daniel Reynolds-2]

I'll chime in with my 2 cents...

I operate 99.9% CW. I bought the KAF2 before the KDSP2 was released. I
originally wanted the KAF2 for both the clock feature and the audio filter
feature (I had money then, and wanted as many features as I could get in my
K2/QRP). Now I seldom use either the clock or audio filter. If I use the audio
filter, I'll use it at the wider setting (AF1?) - the narrow setting I might
use for really rough conditions with wall-to-wall signals - but it generally
doesn't see much use. The clock - well ... let's just say that since I bought
my Casio G-Shock/Waveceptor/Tough Solar watch ... I get very accurate GMT/UTC
from my wrist now.

Would I buy the KAF2 now? Probably not - since the IF filtering does 99% of the
work. BUT - first filter setting does a very nice job of rolling off the 'hiss'
that you'll hear in a pair of stereo headphones ... so it does make it much
more comfortable for those that must operate for a long period of time. For
this reason - I'll be keeping the KAF2.

If I was interested primarily in SSB - I think I'd probably get the DSP for the
simple reason that it will handle noise reduction and filter out heterodynes
that always seem to be a factor in SSB reception.

73!
Daniel AA0NI
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